负载型铈钛SCR催化剂反应机理探究

摘要

采用水热法合成了TiO2纳米颗粒,并负载了CeO2进行选择性催化还原(SCR)氮氧化物的实验研究,发现TiO2纳米颗粒为载体时,催化剂在整个温度区间内的活性都高于商用P25为载体的催化剂.采用原位红外对CeO2/TiO2催化剂SCR反应机理进行相关研究,发现在250℃下该反应主要遵循Eley-Rideal反应机理,即吸附于Lewis酸性位点上的NH3与气相NO发生反应生成N2和H2O,被还原的Ce3+与O2发生作用重氧化为Ce4+.%CeO2 supported on TiO2 nanoparticle synthesized using hydrothermal method was tested for the selective catalytic reduction (SCR) of NO.In comparison with the catalyst prepared using commercial P25 support,CeO2/TiO2-nanoparticle catalyst presented better NO conversion in the whole temperature region.At 250 ℃,Eley-Rideal mechanism contributed mostly for the reaction,in which NH3 coordinated on Lewis acid site reacted with gaseous NO to produce N2 and H2O.The reduced Ce3+ species were re-oxidized to Ce4+ by gaseous O2.